Stabilized asbestos containing vinyl halide resin compositions



United States Patent O lewd:

3,104,786 STABILKZED AS ESTQS CQNTAENINS VINYL HALTDE RESIN CMSTTGNSJames P. Eculiin, Pompton Lakes, Ni, assigncr, by mesne assignments, taTenneco Chemicals, inn, a corporation of Delaware No Drawing. Filed(Pct. 3, 1962, Ser. No. 227,999 9 (Ziaims. (Cl. 260-411.)

This application is a continuation-in-part of copending applicationSerial No. 34,614, now US. Patent No. 3,084,- 135, which was filed onJune 8, 1960.

This invention relates to vinyl halide resin compositions. Moreparticularly it relates to vinyl halide resin compositions that areresistant to the deteriorating effects of heat.

Vinyl halide resins have properties that make them desirable materialsfor use in a wide variety of applications. For example, their excellentabrasion resistance, high gloss, and good resistance to water and toalkalies have resulted in their use in floor coverings, wall coverings,shoe soles and heels, and the like. The vinyl halide resins are commonlyfabricated into useful articles by the ap plication of heat in milling,calendering, or molding operations. The resins so treated tend todecompose somewhat at the elevated temperatures required as is evidencedby the development of color. This decomposition is especially pronouncedwhen scrap portions of the resins are reprocessed in apparatus operatedat elevated temperatures. Even though the decomposition on heating maynot detract to any appreciable extent from the physical properties ofthe resins, the discoloration seriously restricts their use in manyapplications. There has there fore arisen a need for stabilized vinylhalide resin compositions that can Withstand without darkening orotherwise deteriorating the heating to which they may be subjectedduring processing as well as subsequent prolonged heating of thefinished product.

In accordance with the present invention it has been found that productshaving excellent resistance to thermal degradation result whendicyandiamide is incorporated into a vinyl halide resin composition.While dicyandiamide can be used to impart heat stability to a widevariety of vinyl halide resin compositions, it is of particular value inthose compositions that contain asbestos or another fibrous inorganicfiller, such as those that are used in the preparation of floorcoverings.

In the practice of the present invention, dicyandiamide can be usedalone or in combination with an s-triaz'ine compound to impart heatstability to vinyl halide resin.

compositions. The s-triazines that may be used in the dicyandiamidestabilizer mixtures are those that have the formula in which R in eachcase represents a hydrogen atom, a phenyl group, an alkyl groupcontaining from 1 to 5 carbon atoms, or a carbon atom in an s-triazinering and R represents an amino group, a substituted amino group such asan alkylamino or a phenylamino group, or a phenyl group. Illustrative ofthese s-triazine compounds are melamine, lower alkylmelamines such asmethylmelamines and propylmelamines, phenylmelamines, benzoguanamine,melam, and melem.

The relative amounts of dicyandiamide and the s-triazine compound thatare present in the stabilizer mixture are not critical. In most casesapproximately 0.1 part to parts by weight of the s-triazine compound arepresent ilhdfldh Patented July 13, 1955 per part by weight ofdicyandiamide. The preferred mixtures contain approximately 0.5 part to3 parts by weight of the s-triazine compound per part by weight ofdicyandiamide.

Salts of the aforementioned compounds may also be used to stabilize thecompositions of the present invention. These include, for example, thecarbonate, hydrochloride, nitrate, and sulfate salts.

The stabilized vinyl halide resin compositions gener ally containapproximately 0.3 part to 10 parts and preferably 1 part to 5 parts byWeight of the stabilizer per 100 parts by weight of the vinyl halideresin.

The vinyl halide resins that may be used in the compositions of thisinvention are the resinous products obtained by the polymerization of avinyl halide in the presence or absence of another polymerizablecompound. The term vinyl halide resin as used herein includes vinylhalide homopolymers, such as polyvinyl chloride and polyvinyl bromide,as well as copolymers, such as those formed between a vinyl halide andat least one polymerizable compound, such as vinyl acetate, vinylpropionate, vinyl butyrate, vinylidene chloride, styrene, methylmethacrylate, dialkyl fumarate or maleate, and the like. The vinylhalide used is ordinarily and preferably the chloride, but the bromideand fluoride may also be used. The copolymers useful in the practice ofthis invention are those prepared from at least 70% of vinyl halide andup to of the other polymerizable compound.

A wide variety of inorganic fillers including both fibrous andnon-fibrous fillers may be used in the novel vinyl halide resincompositions. While either type of filler can be used as the soleinorganic filler, the compositions pref erably contain both fibrous andnon-fibrous fillers.

The fibrous fillers that may be present in the stabilized vinyl halideresin compositions include asbestos and the mineral wools. Asbestos isthe most commonly used and the preferred fibrous filler. It is usuallypresent in the composition in the amount of approximately 50 to 200parts and preferably to 150 parts by weight per parts by weight of thevinyl halide resin. Any of the commercially available grades of asbestoswhich are used in the preparation of floor covering compositions may beused in the practice of this invention.

The useful non-fibrous inorganic fillers include the many materials thatare commonly employed as fillers by the plastics industry. Theseinclude, for example, calcium carbonate, calcium sulfate, calciumsilicate, barium carbonate, barium sulfate, silica, china clay, kaolin,fullers earth, and magnesium silicate as Well as such pigments astitanium dioxide, lead chromate, and iron oxide. The non-fibrous fillersare generally used in amounts ranging from approximately 50 to 300 partsand preferably from 100 to 200 parts by weight per 100 parts by weightof the vinyl halide resin. While a single non-fibrous filler may beused, a mixture of two or more of these fillers which includes at leastone pigment is most often used.

In addition to the novel stabilizer and the inorganic filler, the vinylhalide resin compositions may contain other additives that areordinarily employed in the preparation of such compositions. Forexample, a plasticizer, such as dioctyl phthalate, dibutyl sebacate, ortricresyl phosphate, may be used in the amount of approximately 5 to 100parts by weight per 100 parts by weight of the vinyl halide resin, withapproximately 15 to 50 parts preferred. Other heat and light stabilizersfor vinyl halide resins, such as metal soaps, metal phenates, andorganic phosphites, may also be present in the vinyl halide resincompositions. Extenders, solvents, binders, dyes, and the like may bepresent in the amounts ordinarily employed for the purposes indicated.

The stabilizers of the present invention may be added to the vinylhalide resin compositions in any convenient is I way. For example, thevinyl halide resin, stabilizer, and other ingredients may be mixed withor without the aid of a volatile solvent and the resulting mixturemilled .on

rolls at 200 F. to 350 F. until it is homogeneous. The stabilized resinmay then be removed from the mill in the form of a film or sheet of thedesired thickness and may be used as such or subjected to a polishing orembossing 1 treatment.

The invention is further illustrated by the example that follows. It isto be understood, however, that this example is not to be construed asbeing limitative, but is furnished merely for purposes of illustration.

EXAMPLE To a mixture of 100 parts by weight of an 80% vinyl chloride-20%vinyl acetate copolymer, 100 parts by weight of asbestos, 160 parts byWeight of granular calcium carbonate, 18 parts by weight of dipropyl-eneglycol dibenzoate, 2.5 parts by weight of epoxidized soybean oil, and 12parts by weight of titanium dioxide was added 1 part by weight of astabilizer. The mixture of ingredients was blended at room temperatureand then charged to a two-roll, steam-heated difiterential speed millwhose roll surface temperature was maintained at 300 F. The mixture wasmilled for 5 minutes and then removed from the rolls as afiexible,'homogeneous sheet, 0.045

specimens with a rating of 1 indicating a pale gray color which is theinherent color imparted by the asbestos and other fillers to the vinylhalide resin and indicating a very dark gray color, the darkening beingthe manifestation of thermal degradation.

atoms, and a carbon atom inan s-triazine ring and R represents a memberselected from the group. consisting of an amino group, an alk-ylaminogroup, a phenylamino group, and a phenyl group; and'the salts of saidstabilizers in the amounts of 50 to 200 parts by weight of asbestos and0.3 to 10 parts by weight of said stabilizer, all'parts per 100 parts byweight of said vinyl halide resin..

2. The heat-stableresinous composition of claim 1 wherein the vinylhalide resin is a vinyl chloride-vinyl acetate copolymer. l

3. The heat-stable resinous composition of. claim 2 wherein thestabilizer is dicyandiamide.

4. The heat-stable resinous composition of claim 2 wherein thestabilizer .is a mixture-of dicyandiamide; and melamine in the amountsofapproximately 0.1 part to 10 parts by weight of melamine. per part byweight of dicyand-iamide. 7

5. The heat-stable resinous-composition of;claim 2 wherein thestabilizer is a mixture of dicyandiamide and benzoguanamine in theamounts of approximately 0.1 part to 10 parts by weight ofbenzoguanamine per part by weight of dicyandiamide. p

6. A heat-stable resinous composition comprising a vinyl halideresin,asbestos, a non-fibrous inorganic filler,

and a stabilizer selected from thexgroup consisting of dicyandiamide;mixtures of dicyandiamide and ans-triazine having the formula group, analkylamino group, a phenylamino group, and

a phenyl group; and'the salts of said stabilizers in the 1 Heatstability of compositions containing 1% of stabilizer Color afterIndicated Number of Minutes at 300 F.

Stabilizer Dicyandiamide 1 1 1 1 1 1 1 1 1 2 2 1/1 Mixture ofDicyandiamide and Melamine 1 1 1 l 1 1 1 1 1 1 2 Urea (ComparativeStabilizer) 1 3 4 6 8 8 8 8 8 8 8 The data in the foregoing table showthat dicyandiamide and a dicyandiamide-melamine mixture when used asstabilizers for asbestos-filled vinyl halide resins formed productshaving excellent heat stability. The comparative stabilizer urea formeda composition that had good initial color but that had poor heatstability.

I claim:

1. A heat-stable resinous composition comprising a vinyl halide resin,asbestos, and a stabilizer selected from the group consisting ofdicyandiarnide; mixturesof dicyandiamide and an s-triazine having theformula wherein R ineach case represents a member selected from the.group consisting of a hydrogen atom, a phenyl group, an alkyl groupcontaining from 1 to 5 carbon wherein R in each case represents a memberselected from the group consisting of a hydrogen atom, a phenyl group,an alkyl group. containing from 1 .to .5 carbon atoms, and a carbon atomin an s-triazine ring and R represents a member selected from the groupconsisting of an amino group, an alkylamino group, a phenylamino group,and a phenyl group; and the salts of said stabilizer in the amount of 80to 150 parts by weight of asbestos, 100 to 200 parts by weight of saidnon-fibrous inorganic filler component, and l to 5 parts by weight ofsaid stabilizer, all parts per 100 parts by weight of said vinyl halideresin.

8. The heat-stable resinous composition of claim 7 wherein thestabilizer is dicyandiamide.

9. The heat-stable resinous composition of claim 7 wherein thestabilizer is a mixture of dicyandiamide and melamine in the amounts of0.5 part to 3 parts by weight of melamine per part by Weight ofdicyandiarnide.

References @itezl the Examiner UNITED STATES PATENTS 2,837,490 6/58Hecker 260-41 5 FOREIGN PATENTS 653 5/52 Germany.

OTHER REFERENCES Smith, Stabilizers for Vinyl Polymers, BritishPlastics, 0 August 1954, pages 307-311.

MORRIS LIEBMAN, Primary Examiner.

1. A HEAT-STABLE RESINOUS COMPOSITION COMPRISING A VINYL HALIDE RESIN,ASBESTOS, AND A STABILIZER SELECTED FROM THE GROUP CONSISTING OFDICYANDIAMIDE; MIXTURES OF DICYANDIAMIDE AND AN S-TRIAZINE HAVING THEFORMULA